1. Field of the Invention
The present invention relates to a transmission comprising a hydraulic pump connected to the crankshaft of an engine, a hydraulic motor having a motor output shaft coaxial with the hydraulic pump and connected to the hydraulic pump by a closed circuit, and a static, hydraulic continuously-variable-speed transmission mechanism contained in a casing with its axis in parallel to the crankshaft.
2. Description of Background Art
A transmission similar to the instant transmission is disclosed in, for example, Japanese Patent Laid-open (Kokai) No. 4-203554.
In the transmission disclosed in Japanese Patent Laid-open (Kokai) No. 4-203554, the output shaft of a hydraulic motor included in a static, hydraulic continuously-variable-speed transmission mechanism serves as the output shaft of the transmission. Therefore, the static, hydraulic continuously-variable-speed transmission mechanism must have a large torque capacity to provide the transmission with a large transmission gear ratio and, consequently, the static, hydraulic continuously-variable-speed transmission mechanism inevitably has a large size. If the transmission is provided with a static, hydraulic continuously-variable-speed transmission having a small torque capacity, the transmission gear ratio of the transmission is variable in a narrow range of transmission gear ratio.